Thanks Ian.
I think my original concern was that the whining was a sensor, as that's what I thought the electrical connection was for (I'd not realised it was an electronic throttle at the time).
I've also read earlier today that with the key in position II, the accelerator pedal will control the throttle, even if the engine isn't running. This can make it possible (with an accomplice in the driver's seat) to inspect or spray some throttle cleaner without having to dismantle anything. In the end, I did remove the throttle body to have a look, and it was a very easy job (only the electrical plug and air pipe to remove first on my particular engine).
cheers.

I probably can't say for sure what component is making that noise, but what I can say is that my 2010 1.6 TDCi Focus (that I've had since new) has always made that noise, and given that it's been running perfectly since new, I'm inclined to say the noise is normal. To clarify, it's a sort of pulsed whining with some clicks and clunks.
One component that will make the occasional noise after driving is the diesel particulate filter 'doing it's thing', although I don't think that happens very often. The noise I hear each time (and the one in your video) is probably one or more components performing a sort of shutdown routine. Maybe certain parts just need to reset themselves, or a few sensors are making some final checks before the engine management system puts everything to sleep. If you google this topic, you'll find lots of people have asked the same thing about TDCi engines.

Thanks Peter - sorry, I meant to acknowledge your previous post, as it was reassuring
Apart from hesitation when moving from standstill (which isn't serious, but I'm still investigating as I like all to be perfect), it's all running very smoothly, and idles well at 750rpm once warm. So I agree that the throttle is probably working OK.
I feel I could probably just leave it all alone now, as it's a very nice drive now that I've renewed a number of parts. I've got some more questions, but will start other topics here....cheers.

I think I've figured this out. The electric connection is simply the power source for the entire throttle body - as it's a 'fly by wire' accelerator. So this is powered with the key ignition switch in position II and III, hence there is a noise as soon as it's powered up, before the engine comes on. I don't know whether the electrical whining noise is a problem, but as it all seems to work, I won't worry about it.
thanks for the help.

Thanks guys - I'll refrain from any tinkering in case I introduce any other issues ;)
This engine consistently idles OK at around 750rpm (after warming up) and doesn't hesitate at any rev, so seems to be happy.
The bit that still concerns me slightly is that it makes this noise when the engine isn't running. My very rudimentary understanding is that with ignition on (e.g. position III), and engine not running, the ECU will be powering sensors, and doing some monitoring, but not 'actuating' anything, especially on a cold engine.

I've recently acquired a C-Max with 1.8 Duratec HE (66k on clock). It runs very smoothly, but at idle it sounds like a pulley bearing is knackered (typical noise coming from aux belt area).
My C-Tek charger tell me that the charge voltage has an issue, and I've measured this at 13.8V with the engine running.
My question is this: Is it possible that a bearing fault on one of the pulleys (or the component turned by the pully) is causing drag on the aux belt, which in turn causes the alternator to turn too slowly, hence the low charge voltage ? I actually doubt this, as I still only get 13.8V even at high engine revs.
Obviously, there's a possibility that the alternator itself is on its way out, but is there any way to isolate it as a cause of the problem ? I'm reluctant to replace it through a process of elimination, only to find there's something else causing the noise, e.g. water pump. But perhaps the 13.8V output tells me it needs replacing anyway ?

I'm trying to locate the cause of a whining noise coming from the front of the engine.
This noise appears when I turn the key to position III, but without the engine starting. If I then turn the ignition switch off again, the whining disappears with a 'clonk' noise. It's not always a constant whine - sometimes it sounds like its pulsing.
I'm fairly sure it's coming from a component positioned on the main air intake. If I first remove the lead (as per attached photo), and then turn the key, there's no noise.
I'm guessing that's some sort of air mass flow sensor ?
Otherwise, the engine (1.8 Duratec 125PS) runs very smoothly, apart from (I think) a worn pulley bearing on the auxiliary belt side.

My C-Max's EPB works fine, but makes a bit of a 'groaning' noise when applying the rear brakes.
I've only just got this car (2005 Ghia) so have no experience of what it would sound like new.
Does anyone know whether it's worth me trying to apply some lube/grease ?
I'm assuming there is a motor, some type of worm drive or rack-and-pinion, some 'stop' sensors and of course the cables that go to the brake calipers. I wouldn't want to dismantle anything as I believe they're 'set' to the car. I guess there's no risk of me upsetting anything simply by dropping it down from the boot floor and taking a peak ?

Just in case anyone's still interested in fixing this for the cheapest method possible, here's the microswitch you need:
http://www.maplin.co.uk/p/sub-miniature-lever-microswitch-gw67x
This fits perfectly in the plastic housing of the release switch for my 2005 Focus C-Max - really snug, so didn't even need any glue. This particular microswitch is the metal 'level' type. I aligned the metal plunger pin of Ford switch with the end of the microswitch's level. It was just a case of pushing the microswitch far enough into the plastic housing, such that it's not possible for the metal plunger pin to overstress the microswitch.
In you're not aware, you need to solder the two black cables to the middle and end (common) contacts on the microswitch. You might need a continuity meter to find out which end is the 'common' contact.
I just need to get some proper electrical sealant to protect the wires. Rather annoyingly, when purchasing the microswitch, I ask for something to seal it. The only sealant Maplins could sell me was bathroom silicon sealant ! I asked them if they have liquid electrical tape, and they'd never heard of it ! I guess that sums up what Maplins is becoming ;)
Oh, I should also point out that for a measly £11, you can now replace the entire switch. To be honest, I think this is worth paying for, especially as you don't need to faff around trying to seal up your original switch. I wish I'd seen these on eBay before doing it the hard way.
http://www.ebay.co.uk/itm/FORD-CMAX-TAILGATE-BOOT-RELEASE-SWITCH-CONTACT-HANDLE-LATCH-1346324-C-MAX-/272137837476

Looking back to the problems I was having, I'm putting it down to a combination of slightly aging battery and lack of experience. The first thing I did was 'realise' that modern cars do simply drain the battery more than older cars when parked. This surprised/annoyed me, but now I just live with it. As advised here, I suspected that the battery was beyond its best having been flatted a few times, so bought a new Bosch S5 Silver, which wasn't cheap at £100, but straight away higher capacity than the original. Like Stoney871, the original battery was 4 years old when I replaced it with this new S5. I too had never seen any low battery lights, despite issues. I then purchased a CTEK MXS 5.0 'smart' charger, and now when I go on holiday for, say, 2 weeks, I run the car's battery through a 'conditioning' cycle when I get back. I also run through this cycle every couple of months, as the car is mainly used for short journeys (my wife's daily commute). I now think a modern diesel like my Focus cannot simply rely on alternator battery charging alone when mainly driven in slow traffic each day. With the CTEK MXS 5.0, my battery now consistently stays above 12.6/12.7V after being parked overnight, which is just about perfect in my view. As mentioned above, I think if it starts dipping to 12.4V it might be necessary to do more than simply driving the car to recharge the battery. It's too early to say yet, but I'm confident that an intelligent charger like the MXS 5.0 does improve the battery's lifespan and performance, so will pay for itself in, say, 10 years - and more if you have more than one car or battery (I also use it to top up a leisure battery I take camping to power the fridge). Another little tip - I wanted to get a decent phone charger, and went with the an item by Capdase called the T2 charger/monitor which displays battery voltage. We leave this plugged in all the time so we can view the current battery voltage, which might seem daft considering what I've said before, but this charger has an insignificant drain on the battery (couldn't detect any difference in drain using an ammeter). I've compared its voltage readout using an expensive DVM on the battery, and it's spot on, hence I'm confident in saying my car battery is always around 12.6V when parked. Oh, and one final point, when I spent time a year so back monitoring the battery at different times, I noticed that there are about 4 different levels of battery consumption when the car is parked : engine is off, but main electrics still on (Power button pressed on without clutch pedal) engine is off (Power button off) but car not locked/alarmed engine is off and car locked/alarmed same a 3. but after being left for about 20 minutes, i.e. sleep modeThere's a considerable difference in battery current drain comparing the above situations (can't remember exact figures now). So anything preventing the car reaching level 4. will drain battery excessively. Symptoms of it not going into sleep mode are the main LED dash board console staying on all the time, i.e. faulty boot closure sensor. Good luck !

I know what you mean, it does just sound like I'm being a bit daft - but on previous cars we used to leave the same Garmin unit plugged in all the time without ever flatting the battery. In fact, this is the first car I've had (since my old RS Mexico) that has flatted the battery just while parked up overnight. It could just be that I need to get used to more modern vehicles, i.e. maybe they use a bit more power when parked, i.e. ECU, alarm and any other electric gizmos that still draw some current. So I'm just wondering if people find that their newer cars have more problems with batteries going dead, just through general, but perhaps slightly careless use, as in my case. I mean how much electricity can a SatNav drain while on charge ? Surely a car battery has the capacity to charge a thousand SatNavs ?